If you get error message here because some device efibootmgr can’t run on chroot. We will do this after fist time boot up new system. But now we need copy grubx64.efi to /boot/efi: (If you not get any error skip this step)

cp /boot/efi/EFI/arch_grub/grubx64.efi /boot/efi/shellx64.efi

Configure bootloader:

grub-mkconfig -o /boot/grub/grub.cfg

Set root password:

passwd

Reboot system:
exit
umount /mnt/boot/efi
umount /mnt
reboot

If you not have any error on “grub-install” step. You can see BIOS boot option have new one and can set boot from new device.

If you get error on “grub-install” step need use below way to fix it.
Boot in BIOS use “Launch EFI shell from filesystem device” and select your hard disk.
After boot in new system use below command to set up efi boot: